Fair enough, at a 15.3 cents premium over regular gas, the initial extra cost of a diesel engine option, higher repair and maintenance costs of a diesel, worrying about Urea refills, and the pathetically slow off the line acceleration and highway merging ability, I wouldn't touch one.
In summer, diesel will likely cost about the same as gasoline. It's a similar pattern every year.
Where both options are available in the same car (Jetta!) the diesel option costs less than the hybrid option ... and they sell a lot more TDI than hybrid.
Regarding the DEF, most diesels have the DEF tank sized so that it will last about as long as the oil change interval, and you can get the stuff everywhere now and it's cheap. Hardly anything to "worry about".
My Jetta cost no more to maintain over its lifetime than the gasoline equivalent would have.
And it certainly wasn't "pathetically slow" ... The Prius, on the other hand, feels dead. I know that if you go by the numbers, it's decent (10-ish seconds to 100 km/h). It just feels dead.
I towed two bikes in my trailer with a car full of stuff to Deals Gap and back many times with that car, and with that much load, it was pretty much 5th gear on cruise control all the way to Cincinnati and only down to 4th a few times on the really steep sections south of that. Try that with a Prius.
Hybrids, batteries, can only see these improving as it is clearly an emerging technology. Most manu's warranty the battery for 8-10 years, with some offering "lifetime". If I were to choose a particular model, I would watch the quality ratings closely while my car remains under warranty. If the car has a failure rate that concerns me, I'd trade it in for a newer model before my 10 years were up. Not a big deal.
In other words, you'll trade it in before the additional cost up front had been amortized ... and if the reliability rating is bad then everyone knows it and resale value will be in the toilet.
I'm not anti-hybrid, I'm in favor of whatever works, and honestly most people are better off just buying the regular model with a modern-design gas engine, be it Ecoboost or Mazda Skyactiv or VW TSI or Fiat Multiair or some such thing.
With the aforementioned Jetta ... if I were to buy one today, I'd simply buy the standard model with the new 1.8 TSI gas engine and manual transmission. No hybrid no TDI no nothing. The 1.8 TSI is within around 10% - 15% of the fuel consumption of the TDI and it costs less to buy (it's the new one-up-from-base engine) and there's a lot less stuff to break. It doesn't have the trailer-towing and hill-climbing grunt of the TDI, that's the only down side that I can see.
Several auto manufacturers are working on the next generation of direct-injection spark-ignition internal combustion engines that operate as a halfway-house between diesel and gasoline engines, and will likely be operating on gasoline but with either compression-ignition or spark-ignition depending on operating conditions. These are probably 3 or 4 years away from production.
